How to calibrate the thermometer and humidity meter: 1. First, take the thermometer and humidity meter and observe the dial of the thermometer and humidity meter. There will be 2-3 buttons on the dial, one is the selection button and the other is the adjustment button. 2. Then press the left button to enter the adjustment mode. First adjust the parameter to zero. Generally, the display is -0.00. If it is the indicated type, the pointer will be at the 0 scale after adjustment. 3. Then find a standard thermometer and humidity meter and place them in the same environment with the calibrated temperature and humidity. Generally, they are placed for 0.5-3 hours. Multiple thermometers and humidity meters can be calibrated at one time. 4. Observe the indication of the calibrated thermometer and humidity meter and compare it with the standard indication. If the indication is within the error, it is qualified, otherwise it is unqualified.